KR20150013300A - Dust suppressing aggregate - Google Patents

Abstract

Dust inhibition aggregates include core particles and dust inhibitors. The dust inhibitor is disposed around the core particles to inhibit dust formation of the core particles and includes polyurethane. The method of forming the particulate suppression aggregate comprises providing core particles and encapsulating the core particles with polyurethane.

Description

DUST SUPPRESSING AGGREGATE < RTI ID = 0.0 >

Cross reference of related application

This application is related to U.S. Provisional Patent Application No. 61 / 648,707, filed May 18, 2012, 61 / 648,766, filed May 18, 2012, and 61 / 648,884, filed May 18, 2012 And their patent applications are incorporated herein by reference in their entirety.

This application is related to the following US patent application, assigned to the same assignee, each of which is incorporated herein by reference in its entirety: " ENCAPSULATED PARTICLE " filed on May 17, Quot ;, which claims priority to U.S. Provisional Patent Application No. 61 / 648,697, attorney control number PF-72188 / 065322.00185, and inventor Alice Hudson, Lillian Senior, Bernard Sencherei ), And Victor Granquist, United States Patent Application No. < RTI ID = 0.0 > ***. ≪ / RTI >

1. Field of the Invention

The present invention generally relates to dust inhibiting aggregates. More specifically, the present invention relates to dust suppression agglomerates comprising a dust inhibitor disposed around core particles for inhibiting dust formation of core particles.

2. Description of Related Technology

Fertilizers containing particulate matter tend to produce dust during manufacture, handling, storage and application. Dust is generated when the particulate material is broken into smaller particles. In particular, fertilizers containing ammonium phosphate, calcium phosphate, ammonium nitrate, potassium nitrate, potassium chloride, potassium sulfate and the like tend to produce significant levels of undesirable dust.

The generation of dust during the manufacture, handling, storage and application of fertilizers is problematic for a number of reasons. Typically, the resulting dust is ultimately discarded, i. E., It does not reach its intended use. However, the generated dust is typically introduced into the air and the surrounding environment, which can lead to health and environmental concerns. In an effort to reduce these wastes and to alleviate these concerns, dust inhibitors are often applied to fertilizers to reduce dust generation.

The dust inhibitor is typically a liquid such as oil, but may be a solid such as wax. Specific examples of dust inhibitors are petroleum residues, hydrogenated mineral oils and waxes. Dust inhibitors are typically spray applied to the fertilizer bed. Spray application of the dust inhibitor onto the fertilizer phase is carried out in combination with stirring in a rotary drum or tumbler. Stirring facilitates coating of the dust inhibitor on the surface of the fertilizer phase, i.e., the particulate material.

So far, treatment of fertilizers has focused on dust inhibitors such as mineral oils and waxes. There are disadvantages associated with such dust inhibitors. Liquid dust inhibitors such as mineral oils can volatize over time and / or move into fertilizers and lose their effectiveness. Solid powder inhibitors such as waxes are difficult to handle, require specialized application equipment, can cause lumps or agglomeration, and can inhibit solubilization / release of once applied fertilizers.

Therefore, there remains a need to develop an improved dust inhibitor.

Summary and Advantages of the Invention

The present invention provides dust-inhibiting aggregates comprising core particles and a dust inhibitor. The dust inhibitor is disposed around the core particles to inhibit dust formation of the core particles and includes a polyurethane. The method of forming the particulate suppression aggregate comprises providing core particles and encapsulating the core particles with polyurethane.

The polyurethane protects the core particles and minimizes dust generation by the core particles. The polyurethane is a solid and does not lose its effect as a dust inhibitor because it is volatilized over time and / or does not migrate into fertilizer. In addition, the polyol and isocyanate components that form the polyurethane promote the consistent and minimal encapsulation of the core particles by the polyurethane, forming a polyurethane that is durable and prevents clumping and agglomeration of the core particles. The polyurethane acts to protect the core particles and to prevent dust generation, but the polyurethane enables rapid penetration of water and does not significantly inhibit the dissolution / release of the core particles.

details

The present invention provides dust suppression aggregates. Dust inhibition aggregates include core particles and dust inhibitors. Dust inhibition aggregates typically do not have a liquid dust inhibitor. The core particles typically comprise a fertilizer which may comprise calcium, magnesium, nitrogen, phosphate, potassium, sulfur and combinations thereof. The fertilizer may be selected from the group of nitrogen fertilizers, phosphorus fertilizers, potassium fertilizers, sulfur fertilizers, and combinations thereof, such as mixed fertilizers. Suitable fertilizers include ammonium nitrate, urea, ammonium nitrate, urea ammonium nitrate, potassium nitrate, calcium ammonium nitrate, calcium phosphate, phosphoric acid, monoammonium phosphate, ammonium polyphosphate, ammonium phosphate sulfate, But are not limited to, potassium nitrate, potassium chloride, potassium sulfate, ammonium sulfate and sulfuric acid, and combinations thereof. Typical non-limiting examples of fertilizers include urea and monoammonium phosphate.

The core particles may also contain other ingredients for use in herbicides, insecticides, fungicides, and agricultural applications. However, dust inhibiting aggregates are not limited to use in agricultural applications, and the core particles of the present invention are not limited to the ingredients just described.

The shape of the core particle is not critical, but a core particle having a spherical shape is preferable. Thus, the core particles are typically round or approximately spherical. While the core particles may have any size, the core particles typically have a size of less than about 1 mm when measured according to standard sizing techniques using the United States Sieve Series. 170 to 5/16 in., More typically no. 35 to No. 3 1/2, and most typically no. 18 to No. It has a particle size of 5 mesh. That is, the core particles typically have a particle size of from 0.1 to 7, more typically from 0.5 to 5, and most typically from 1 to 4 mm. The core particles having a round or approximately spherical shape and having such a particle size enable the use of typically lesser inhibitors as compared to core particles having different particle shape and size and the particulate inhibitor typically disposed on the core particle is increased Uniformity and completeness.

The dust inhibitor is disposed around the core particles to inhibit dust formation of the core particles and includes a polyurethane. The polyurethane may be partially or completely disposed around the core particles. The polyurethane comprises the reaction product of an isocyanate component and a polyol component.

The isocyanate component typically comprises an aromatic isocyanate. More typically, the isocyanate component includes, but is not limited to, monomeric and polymeric methylene diphenyl diisocyanates, monomeric and polymeric toluene diisocyanates, and mixtures thereof. Most typically, the isocyanate component is LUPRANATE ^占 M20, commercially available from BASF Corporation, Florham Park, New Jersey.

Loop la carbonate ^® M20 comprises a polymeric diphenylmethane diisocyanate and has an NCO content of about 31.5 weight percent. Polymeric methylene diphenyl diisocyanates, for example the loop la carbonate ^® M20 provides a viscosity of the high degree of cross-linking density and medium. Alternatively, the monomer-methylene diphenyl diisocyanate, such as loops la carbonate ^® M provides a high NCO content with low viscosity and low nominal functionality. Similarly, toluene diisocyanate, such as TDI-loop la carbonate ^® also provides a high NCO content with a low viscosity and also low nominal functionality.

Typically, the isocyanate component has a viscosity of from 1 to 3000, more typically from 20 to 700, and most typically from 50 to 300 centipoise at 25 占 폚. The most typical viscosity of the isocyanate component is 50 to 300 centipoise at 25 DEG C such that the isocyanate component can be sprayed onto the core particles. Typically, the isocyanate component has a nominal functionality of from 1 to 5, more typically from 1.5 to 4, and most typically from 2.0 to 2.7. The most typical nominal functionality of the isocyanate component is from 2.0 to 2.7 to enable efficient reaction and cost-effectiveness of the isocyanate component and the polyol component. Typically, the isocyanate component has an NCO content of 20 to 50, more typically 25 to 40, and most typically 30 to 34 wt%. The NCO content provides a high molecular crosslink density to aid in the formation of polyurethane. The NCO content also provides more chemical bonding per unit mass to improve cost effectiveness. The viscosity, nominal functionality, and NCO content of the isocyanate component may vary outside of the above range, but are typically both integer and fractional values within this range.

For the polyol component, the polyol component typically comprises one or more OH functional groups, typically one or more polyols having two or more OH functional groups. The polyol component may comprise an isocyanate-reactive moiety having at least one NH functional group in addition to, or instead of, OH functional group (s). Typically, the polyol component comprises at least one polyol selected from the group of polyether polyols, polyester polyols, polyether / ester polyols, and combinations thereof. However, other polyols may be used.

In one embodiment, the polyol component comprises a high molecular weight (HMW) polyol. HMW polyols are typically high molecular weight primary hydroxyl terminated polyols. HMW polyols are typically disclosed as trifunctional initiators of one or more non-amine based moieties. Suitable initiators for the initiation of HMW polyols include, but are not limited to, glycerin, trimethylol propane, propylene glycol, dipropylene glycol, isopropylene glycol, sorbitol, sucrose, and the like.

The HMW polyol has a number average molecular weight, M _n , of greater than 1400 g / mol, since this number average molecular weight, M _n , tends to improve the performance characteristics of the polyurethane. This number average molecular weight, M _n , tends to impart elasticity, abrasion resistance and controlled release properties to the polyurethane. Typically, the HMW polyol has a number average molecular weight, M _n , greater than 400 g / mol, more typically 400 to 15000, and most typically 500 to 7000 g / mol. Typically, the HMW polyol has a viscosity of 100 to 2000, more typically 150 to 1800, and most typically 200 to 1600 centipoise at 25 占 폚. Typically, the HMW polyol has a nominal functionality of 1.6 or greater, more typically 1.8 to 5, and most typically 1.8 to 3.2. Typically, the HMW polyol has an OH number of from 20 to 300, more typically from 23 to 275, and most typically from 25 to 250 mg KOH / g. The number average molecular weight, viscosity, nominal functionality, and OH value of the HMW polyol can be any value outside of the above range, but are typically both integer and fractional values within this range. Non-limiting examples of typical HMW polyols are commercially available including fluorescein La Colle (PLURACOL) ^® 220, La Colle flu ^® 2010, and La Colle flu ^® 4156 from BASF Corporation, New Jersey, USA Flor ham Park material.

The polyol component may also comprise a catalytic polyol. The catalytic polyol is different from the HMW polyol. Catalytic polyols are referred to as "catalytic" polyols because they can be used in place of catalysts that promote the chemical reaction of the isocyanate component and the polyol component. In other words, the polyol component comprising the catalytic polyol is typically chemically reacted with the isocyanate component at a lower temperature in the presence of a less catalyst (even without a catalyst), as compared to a polyol component that does not include a catalytic polyol. Catalyst polyols are typically derived from amine-based initiators. The catalytic polyol may be formed with more than one initiator. In one embodiment, the catalytic polyol is derived from a dipropylene glycol initiator. In another embodiment, the catalytic polyol may be co-initiated with dipropylene glycol. Although not wishing to be bound by theory, it is believed that the amine content of the catalytic polyol promotes the reaction of the isocyanate component and the polyol component.

The catalytic polyols may also contain alkylene oxide substituents. Examples of suitable alkylene oxide substituents are ethylene oxide, propylene oxide, butylene oxide, amylene oxide, mixtures thereof, alkylene oxide-tetrahydrofuran mixtures, epihalohydrins, and ar Alkylene styrene.

One embodiment of the catalyst polyol formed from the amine-based initiator typically has a viscosity at 25 DEG C of from 500 to 75,000, more typically from 32,000 to 72,000, and most typically from 42,000 to 62,000 centipoise; Typically greater than 2.5, more typically 2.75 to 10, and most typically 3 to 4 nominal functionalities; 200 to 950, more typically 250 to 850, most typically 750 to 800 mg KOH / g of OH; And a number average molecular weight of less than 1400 g / mol, more typically 100 to 1120, and most typically 192 to 392 g / mol. The viscosity, nominal functionality, OH number, and number average molecular weight of the catalytic polyols of this embodiment can vary outside of the above range, but are typically both integer and fractional values within this range. An example of a suitable catalyst, a polyol of the present embodiment is commercially available under the trade name Quad-roll (QUADROL) ^® from BASF Corporation of New Jersey, USA Flor ham Park material.

Another embodiment of the catalytic polyol is formed from an aromatic amine-based initiator. The aromatic amine-based initiator has the formula:

Wherein each of R ₂ to R ₆ independently represents one of an amine group and a hydrogen atom, as long as at least one of R ₁ to R ₆ is an amine group. In the formula, R ₁ includes _one of an alkyl group, . Thus, it is to be understood that R < ₁ > may be any compound comprising any one of an alkyl group, an amine group or hydrogen, or combinations thereof. It is to be understood that R ₂ to R ₆ need not be the same and may each contain an amine group or hydrogen. Further, the term "amine group" is to be understood as a whole referred to RNH and NH _2.

The aromatic amine-based initiator may include, but is not limited to, toluene diamine. Toluene diamines typically have the following structures:

But are not limited to, toluene diamine, such as 2,3-toluenediamine, 2,4-toluenediamine, 2,5-toluenediamine, 2,6-toluenediamine, 3,4-toluenediamine, 3 , 5-toluenediamine, and mixtures thereof.

Aromatic amine-based initiators tend to provide, for example, fully miscible catalytic polyols that are miscible with isocyanate components. The miscibility of the isocyanate component with the catalytic polyol derived from an aromatic amine-based initiator tends to be due to two main effects. First, miscibility is influenced by the London force, which produces transient induced dipoles between the catalytic polyol and similar aromatic moieties of the isocyanate component. The transient induction dipole allows effective mixing of the catalytic polyol and the isocyanate component. Secondly, miscibility is influenced by the planar geometry of the catalytic polyol and the aromatic moiety of the isocyanate component, which enables complementary lamination of the catalytic polyol and the isocyanate component. Thus, the isocyanate component and the polyol component are effectively mixed.

Embodiments of catalyst polyols formed from aromatic amine-based initiators typically have a viscosity at 25 DEG C of from 400 to 100,000, more typically from 450 to 10,000, and most typically from 500 to 2500 centipoise; Typically greater than 2.5, more typically 2.75 to 10, and most typically 3 to 4 nominal functionalities; 200 to 950, more typically 250 to 850, most typically 750 to 800 mg KOH / g of OH; And a number average molecular weight of less than 1400 g / mol, more typically 100 to 1120, and most typically 639 to 839 g / mol. The viscosity, nominal functionality, OH number, and number average molecular weight of the catalytic polyols of this embodiment can vary outside of the above range, but are typically both integer and fractional values within this range. Examples of suitable polyols catalyst of the present embodiment is commercially available under the trade name ^® 1168 La Colle flu and flu La Colle ^® 1578 from BASF Corporation of New Jersey, USA Flor ham Park material.

When present, the catalytic polyol is typically present in the polyol component in an amount of from 1 to 95, more typically from 65 to 65, and most typically from 15 to 35 parts by weight, based on 100 parts by weight of the polyol component . The amount of catalytic polyol may vary outside of the above range, but is typically both an integer value and a fractional value within this range.

When both the HMW and the catalytic polyol are present in the polyol component, the catalytic polyol is typically present in the polyol component in an amount less than the amount of the HMW polyol. The weight ratio of HMW polyol to catalyst polyol in the polyol component is typically from 1: 1 to 15: 1, more typically from 2: 1 to 12: 1, and most typically from 2.5: 1 to 10: 1. The weight ratio of HMW polyol to catalyst polyol may vary outside of the above range, but is typically both an integer value and a fractional value within this range.

The polyurethane may be formed in the presence of a silicone surfactant. Silicone surfactants are typically polyorganosiloxanes. Non-limiting examples of typical polyorganosiloxanes are alkyl pendent organosilicon molecules comprising a polysiloxane backbone and a polyether backbone. The alkyl pendent organosilicon molecules of this example may be a comb structure or a dendrimer structure.

Silicone surfactants typically improve the wetting of the polyol component and the isocyanate component on the core particles and may thus be described as wetting agents. Silicon surfactants also typically enhance the adhesion of polyurethane to core particles. Additionally, silicone surfactants reduce the aggregation and aggregation of dust suppression aggregates during and after the encapsulation process. Thus, the silicone surfactant promotes more complete encapsulation of the core particles by the polyurethane, facilitates the consistent thickness of the polyurethane, enables formation of a polyurethane with minimal but consistent thickness, By reducing the amount of polyurethane required to coat, the overall amount of isocyanate component and polyol component required to encapsulate core particles into a uniform thickness polyurethane coating is reduced overall and the yield of dust suppression agglomerates encapsulated with a coherent polyurethane coating And minimizes pits and depressions in the polyurethane. Typically, the silicone surfactant is liquid and has a viscosity at 25 DEG C of 100 to 1500, more typically 200 to 1000, and most typically 650 to 850 cSt. The viscosity of the silicone surfactant may vary outside of the above range, but is typically both an integer value and a fractional value within this range.

Specific examples of suitable silicon surfactants, Air Products and Chemicals's, Inc. of Tego commercially available from Goldschmidt AG (Goldschmidt AG) of Essen, Germany material staff (TEGOSTAB) ^® BF 2370, United States pa Allentown material ( Air Products and Chemicals, Inc.) is commercially available beuko (DABCO) ^® DC5043, and NY commercially available from Momentive performance materials (Momentive performance materials) Albany material you can AX (NIAX) ^® silicone from But are not limited to, L-5340 and L-620. In particular, a suitable silicone surfactant is your AX ^® Silicone L-620, a polyalkylene oxide methyl siloxane copolymer. The silicone surfactant may be present in the polyol component in an amount of 0.01 to 10, typically 0.05 to 5, and more typically 0.5 to 1.5 parts by weight, based on 100 parts by weight of all components used in the polyurethane formation. The weight parts of the silicone surfactant may vary outside of these ranges, but are typically both integer and fractional values within the range.

The polyurethane may optionally comprise one or more additives. Additives are typically included in the polyol component, but may be included in the isocyanate component or added separately. Suitable additives for the purposes of the present invention include, but are not limited to, chain extenders, cross-linkers, chain-terminating agents, processing additives, adhesion promoters, antioxidants, defoamers, flame retardants, catalysts, anti-foaming agents, moisture scavengers, molecular sieves, fumed But are not limited to, silica, surfactants, ultraviolet light stabilizers, fillers, thixotropic agents, silicones, colorants, pigments, inert diluents, and combinations thereof. For example, a pigment may be included in the polyurethane. When an additive is included, it can be included in the polyurethane in various amounts.

The polyurethane-containing dust inhibitor is typically present in the dust inhibiting aggregate in an amount of from 0.3 to 5.5, more typically from 0.5 to 3.0, and most typically from 0.7 to 2.0 parts by weight, based on 100 parts by weight of the core particles. The amount of the dust inhibitor comprising polyurethane present in the dust inhibition aggregate may vary outside of the above range, but is typically both an integer value and a fractional value within this range.

Dust inhibition aggregates comprising core particles and polyurethane thereon are typically round or approximately spherical. Dust inhibition aggregates have a size distribution reported as D [4,3], d (0.1), d (0.5) and / or d (0.9), as is well defined and recognized in the art. In various embodiments, the dust inhibition aggregate has a size distribution D [4,3] of 0.5 to 5 mm, 1 to 4 mm, or 1 to 3 mm under the total particle size range of 0.1 to mm. In another embodiment, the dust suppression aggregate has a size distribution d (0.1) of 0.2 to 2 mm, 0.4 to 1.7 mm, or 0.5 to 1.5 mm under the total particle size range of 0.1 to 10 mm. In a further embodiment, the dust inhibition aggregate has a size distribution d (0.5) of 0.5 to 5 mm, 1 to 4 mm, or 1 to 3 mm under the total particle size range of 0.1 to mm. In yet another embodiment, the dust inhibition aggregate has a size distribution d (0.9) of 0.7 to 7 mm, 0.8 to 5 mm, or 1 to 4 mm under the total particle size range of 0.1 to 10 mm. The D [4,3], d (0.1), d (0.5) and d (0.9) size distributions of the dust suppression agglomerates may differ from the above ranges, but are typically 0.5 to 5 mm, 0.2 to 2 mm, 0.5 To 5 mm, and 0.7 to 7 mm, respectively.

The dust suppression performance of the dust inhibitor can be measured. To test the dust suppression performance of the dust inhibitor, the dust value (ppm) of the dust inhibition aggregate is obtained. A 50 g sample of the dust inhibition aggregate is placed in a 125 mL open-glass vial and the dust level is measured. Place the bottle in a Burrell Model 75 wrist-action shaker and shake for 20 minutes at maximum intensity setting (10). After shaking, the sample is weighed and then processed in a dust removal unit. The dust removal unit is 2.5 in. Diameter plastic cup, cup holder, air flow meter and vacuum cleaner. The base of the cup is removed and replaced with a 200 mesh screen. Each sample is placed in a cup, the cup is placed in a holder, and then air is drawn through the sample for 2 minutes at a rate of 9 standard cubic feet per minute using a vacuum cleaner. The sample is then re-weighed. The amount of dust is calculated from the weight difference before and after dust removal. Record the results as the average of two repeated runs.

Typically, dust suppression aggregates have a dust value of less than 3000 ppm, more typically less than 2000 ppm, even more typically less than 1000 ppm, even more typically less than 500 ppm, and most typically less than 250 ppm .

In one embodiment, the dust inhibition aggregate comprises a dust inhibitor in an amount of less than 1 part by weight based on 100 parts by weight of the dust inhibition aggregate and is less than 1000 ppm, more typically less than 750 ppm, and most typically less than 500 ppm Lt; / RTI >

In another embodiment, the dust inhibition aggregate comprises a dust inhibitor in an amount of less than or equal to 2 parts by weight based on 100 parts by weight of the dust inhibition aggregate and is less than 500 ppm, more typically less than 200 ppm and most typically less than 150 ppm ≪ / RTI >

The dust reduction gradient (%) can be obtained using the dust value. The dust reduction gradient is calculated using the following equation:

[(Dust value A - dust value B) / dust value A] X 100

The dust value A is the dust value of the uncoated core particles.

The dust value B is the dust value of the dust suppression agglomerate containing the same core particles.

In other words, when the dust values for core particles and dust suppression agglomerates that are not coated under certain conditions are obtained, the dust reduction ratio (%) is determined by the ratio of the uncoated core particles and the coated core particles, It is the percent difference of the amount of dust. Typically, the larger the dust reduction gradient, the better. In one embodiment, the dust inhibition aggregate comprises a dust inhibitor in an amount of less than 1 part by weight based on 100 parts by weight of the dust inhibition aggregate, and is present in an amount greater than 10%, more typically greater than 50%, and most typically greater than 80% Lt; RTI ID = 0.0 > decreasing < / RTI >

In another embodiment, the dust inhibition aggregate comprises a dust inhibitor in an amount of less than or equal to 2 parts by weight based on 100 parts by weight of the dust inhibition aggregate and is present in an amount of greater than 20%, more typically greater than 60%, and most typically less than 90% Lt; RTI ID = 0.0 > decreasing < / RTI >

The polyurethane in the dust suppression agglomerates has a minimal effect on the dissolution rate of the core particles. That is, the dust inhibitor comprising polyurethane minimally affects the rate at which the core particles are dissolved. The dissolution rate is the amount of core particles that are soluble in water under certain conditions and is typically measured in weight percent, which is described in further detail below.

The dissolution rate is measured by placing 50 g of the dust inhibiting aggregate in a 250 mL plastic bottle. Then 230 g of deionized water is added to the bottle. The plastic bottle is allowed to stand at room temperature (23 DEG C) for 8 hours in a calm state. The liquid sample is then withdrawn and its refractive index is measured using a refractometer. Calculate the amount (grams) of core particles dissolved in each solution sample using refractive index and temperature-corrected standard curves. The dissolution rate (%) is calculated by the following equation using the amount of dissolved core particles:

Dissolution rate (%) = X / (50 - (weight percent of applied dust inhibitor / 2))

X = amount (grams) of core particles dissolved in the solution sample

Weight percent of applied dust inhibitor = 100% x Weight of applied dust inhibitor / dust inhibiting aggregate.

The dissolution rate can be used to determine the dissolution rate gradient. The dissolution rate gradient is simply the difference between the dissolution rate (%) of the uncoated core particles and the dissolution rate of the core particles of the dust suppression agglomerates. In other words, if the dissolution rate for core particles and dust suppression agglomerates that are not coated under certain conditions is determined, the dissolution rate gradient is an absolute value minus the dissolution rate of the uncoated core particles minus the dissolution rate of the dust suppression agglomerates. Typically, the smaller the dissolution rate gradient, the better. The dust inhibitor should inhibit the dust formation of the core particles, but it is typically desired that the dust inhibitor has a minimal effect on the dissolution rate of the core particles. Typically, dust-inhibiting aggregates have a solubility gradient of less than 30, more typically less than 15, even more typically less than 10, and most typically less than 5 after 1 day of aging at 23 ° C water.

The present invention relates to a system for the formation of dust suppression agglomerates in addition to dust suppressing agglomerates and a method for forming dust suppressing agglomerates. A system for the formation of dust inhibition aggregates comprises an isocyanate component, a polyol component and core particles.

The method includes providing core particles and encapsulating core particles with polyurethane. The step of encapsulating the core particles with a polyurethane can be further defined as reacting the isocyanate component and the polyol component to form a polyurethane. Typically, an isocyanate component and a polyol component are mixed, that is, combined and chemically reacted to form a polyurethane. Typically, the isocyanate component and the polyol component react with an isocyanate index of from 90 to 160, more typically from 110 to 140, and most typically from 125 to 135. As is well known in the art, an isocyanate index is defined as the ratio of the actual molar amount of isocyanate (s) reacted with the polyol (s) to the stoichiometric molar amount of isocyanate (s) needed to react with an equimolar amount of polyol . The step of reacting the isocyanate component and the polyol component may be performed prior to encapsulating the core particles with polyurethane. Alternatively, the step of reacting the isocyanate component and the polyol component may be performed simultaneously with encapsulating the core particles with polyurethane.

The isocyanate component and the polyol component may be combined using one or more techniques including, but not limited to, swelling, pan coating, fluid bed coating, coextrusion, mixing, spraying and rotary disk encapsulation. Most typically, the isocyanate component and the polyol component are mixed by spraying in or onto a reaction vessel such as a barrel, drum, mixer, or the like. The polyol component and the isocyanate component may be mixed and sprayed in or on the reaction vessel using a single spray gun or multiple spray guns. In one embodiment, the isocyanate component and the polyol component are impinged at the spray nozzle. The polyol component and the isocyanate component may be sequentially sprayed in or onto the reaction container using a single spray gun and mixed in the reaction container. Alternatively, the isocyanate component and the polyol component may be sprayed in or on the reaction vessel simultaneously or sequentially using different spray guns.

In one non-limiting example, the isocyanate component and the polyol component may be sprayed onto the core particle in the following order: (1) spraying a portion of the isocyanate component onto the core particle; (2) spraying a portion of the polyol component onto the core particles; (3) spraying the remaining portion of the isocyanate onto the core particles; (4) Spraying the remainder of the polyol component onto the core particles. In another non-limiting example, the isocyanate component and the polyol component can be sprayed onto the core particles in the following order: (1) spraying a portion of the isocyanate component onto the core particles; (2) spraying a portion of the polyol component onto the core particles, and at the same time spraying the remaining portion of the isocyanate component onto the core particles; (3) Spraying the remainder of the polyol component onto the core particles.

The method optionally comprises the step (s) of heating the isocyanate component, the polyol component and / or the core particles before, or simultaneously with, the mixing step of the isocyanate component and the polyol component. The isocyanate component, the polyol component, the silicone surfactant and / or the core particles can be heated individually or in combination with one or more of each other. Typically, the isocyanate component, the polyol component and the core particles are heated before or simultaneously with the encapsulation step of the core particles. Typically, the isocyanate component, the polyol component and the core particles are heated to a temperature in excess of 40 DEG C, more typically 45 to 90 DEG C, and most typically 50 to 80 DEG C.

The encapsulation step may be performed once, or it may be repeated. If repeated, the steps need not be the same for each individual epoch. The core particles may be encapsulated once with polyurethane or multiple times with polyurethane. It is contemplated that the core particles may be encapsulated with a polyurethane and one or more additional dust inhibitor. The core particles may be encapsulated, either partially or wholly.

The following examples illustrate the characteristics of the present invention and should not be construed as limiting the invention.

Example

Examples Hereinafter, examples dust suppression aggregates (Examples) A to D are described. Examples A through D include a particulate inhibitor comprising core particles and a polyurethane disposed around the core particles. Examples A to D are formed according to the present invention.

To form Examples A to D, a dust inhibitor comprising a polyurethane is disposed around the core particles. The compositions used to form Examples A to D are shown in grams in Table 1 below. In a first vessel, polyol A is preheated to a temperature of 150 < 0 > F. Preheating the isocyanate in a second vessel to a temperature of 150 < 0 > F. In the third vessel, the core particles A are preheated to a temperature of 150 < 0 > F. When preheated, core particle A is added to a reaction vessel having a roller speed of 26 rpm. When the core particle A is added, the isocyanate is added to the reaction vessel and stirred with the core particle A for 2 minutes. Polyol A is then added to the reaction vessel and stirred with isocyanate and core particle A for an additional 10 minutes. During stirring, polyol A and isocyanate react to form a dust inhibitor comprising polyurethane and disposed around core particle A.

Table 1

Polyol A is a commercially available high molecular weight polyols, La Colle flu ^® 4156 from BASF Corporation in the United States, New Jersey, Flor Parks Ham material.

Isocyanate is commercially available polymeric methylene diphenyl diisocyanate, the loop la carbonate ^® M20 from BASF Corporation of New Jersey, USA Flor ham Park material.

Core Particle A is a commercially available Fertilizer, MicroEssentials MES-z from Mosaic, Plymouth, Minn.

The polyurethane-containing dust inhibitor of Examples A to D encapsulates core particles A to prevent dust formation due to mechanical wear. Further, the dust inhibitor containing polyurethane does not significantly inhibit or interfere with the dissolution of the core particle A.

Examples Hereinafter, examples dust suppression aggregates (Examples) E to U are also described. Examples E to U include a particulate inhibitor comprising core particles and a polyurethane disposed around the core particles. Examples E to U are formed according to the present invention.

To form Examples E to U, a dust inhibitor comprising polyurethane is placed around the core particles. The compositions used to form Examples E to U are shown in grams of the following Tables 2 and 3. One or more polyols and additives are mixed in a first vessel to form a polyol component, which is preheated to a temperature of 150 < 0 > F. Preheating the isocyanate in a second vessel to a temperature of 150 < 0 > F. In a third vessel, the core particles A or B (according to the embodiment) are preheated to a temperature of 150 < 0 > F. Once preheated, the core particles A or B are added to a reaction vessel having a roller speed of 26 rpm. When core particles A or B are added, isocyanate is added to the reaction vessel and stirred with core particles A or B for 2 minutes. The polyol component is then added to the reaction vessel and stirred with the isocyanate and core particles A or B for an additional 10 minutes. During stirring, the polyol component and the isocyanate react to form a dust inhibitor comprising polyurethane and disposed around the core particles.

Table 2

Table 3

Polyol B is commercially available aromatic amine with from BASF Corporation of New Jersey, USA Flor ham park material - is disclosed a polyol, fluorenyl La Colle ^® 1168.

Polyol C is a commercially available high molecular weight polyols, La Colle flu ^® 220 from BASF Corporation, New Jersey, USA Flor ham Park material.

Polyol D is castor oil.

Polyol E is a commercially available aromatic amine with from BASF Corporation of New Jersey, USA Flor ham park material - is disclosed a polyol, fluorenyl La Colle ^® 4650.

Polyol F is a commercially available aromatic amine from BASF Corporation of New Jersey, USA Flor ham park material - a polyol, fluorenyl La Colle ^® GP430 disclosed.

Polyol G is a commercially available aromatic amine from BASF Corporation of New Jersey, USA Flor ham park material - is disclosed a polyol, fluorenyl La Colle ^® 593.

Polyol H is dipropylene glycol.

Additive A is ANTIFOAM A, an anti-foaming additive commercially available from Dow Corning Corporation of Midland, Mich., USA.

Additive B is a molecular sieve, MOLSIV 3A, commercially available from UOP, Des Plaines, Ill., USA.

Additive C is a commercially available silicone surfactant, did AX ^® L-620 from Momentive Performance Materials of Albany, New York material.

Isocyanate is commercially available polymeric methylene diphenyl diisocyanate, the loop la carbonate ^® M20 from BASF Corporation of New Jersey, USA Flor ham Park material.

Core particle B is a urea granule.

The dust inhibitor comprising the polyurethanes of Examples E to U encapsulates the core particles A to prevent dust formation due to mechanical wear. Further, the dust inhibitor containing polyurethane does not significantly inhibit or interfere with the dissolution of the core particles B.

Examples Dust inhibition aggregates (Examples) V to X and Comparative Example A are described herein. Examples V-X include a particulate inhibitor comprising core particles and a polyurethane disposed around the core particles. Examples V to X are formed according to the present invention. Comparative Example A is not formed according to the present invention and is included for comparison purposes.

To form Examples V-X, a dust inhibitor comprising polyurethane is placed around the core particles. The compositions used to form Examples V through X are shown in grams in Table 4 below. One or more polyols and additives are mixed in a first vessel to form a polyol component, which is preheated to a temperature of 150 < 0 > F. Preheating the isocyanate in a second vessel to a temperature of 150 < 0 > F. In a third vessel, the core particles B are preheated to a temperature of 150 < 0 > F. Once pre-heated, the core particles B are added to a reaction vessel having a roller speed of 26 rpm. When core particle B is added, isocyanate is added to the reaction vessel and stirred with core particle B for 2 minutes. The polyol component is then added to the reaction vessel and stirred with the isocyanate and core particles B for an additional 10 minutes. During stirring, the polyol component and the isocyanate react to form a dust inhibitor comprising the polyurethane and disposed around the core particle B.

Table 4

^* Polyol B is commercially available aromatic amine with from BASF Corporation of New Jersey, USA Flor ham park material - is disclosed a polyol, fluorenyl La Colle ^® 1168.

Core Particle B is a commercially available fertilizer, SGN 250 (granular urea) from CF Industries, Deerfield, Illinois. Sieve urea granules with US # 5 and US # 16 sieves to adjust particle size.

A 50 g sample of the dust-inhibiting aggregate of each example is placed in a 125 mL glass vial and the dust value (ppm) is measured. Place the bottle on a BuLel Model 75 wrist shaker and shake for 20 minutes at maximum intensity setting (10). After shaking, the sample is weighed and then processed in a dust removal unit. The dust removal unit is 2.5 in. Diameter plastic cup, cup holder, air flow meter and vacuum cleaner. The base of the cup is removed and replaced with a 200 mesh screen. Each sample is placed in a cup, the cup is placed in a holder, and then air is drawn through the sample for 2 minutes at a rate of 9 standard cubic feet per minute using a vacuum cleaner. The sample is then re-weighed. The amount of dust is calculated from the weight difference before and after dust removal. Record the results as the average of two repeated runs.

The dust reduction gradient (%) is obtained using the dust value. The dust reduction gradient is calculated using the following equation:

[(Dust value A - dust value B) / dust value A] X 100

The dust value A is the dust value of the uncoated core particles.

The dust value B is the dust value of the dust suppression agglomerate containing the same core particles.

The dissolution rate (%) is measured by placing a 50 g sample of the dust inhibiting aggregate of the Example in a 250 mL plastic bottle. Then 230 g of deionized water is added to the bottle. The plastic bottle is allowed to stand at room temperature (23 DEG C) for 8 hours in a calm state. The liquid sample is then withdrawn and its refractive index is measured using a refractometer. Calculate the amount (grams) of core particles dissolved in each solution sample using refractive index and temperature-corrected standard curves. The dissolution rate (%) is calculated by the following equation using the amount of dissolved core particles:

Dissolution rate (%) = X / (50 - (weight percent of applied dust inhibitor / 2))

X = amount (grams) of core particles dissolved in the solution sample

% Coating = 100% x Weight of applied dust inhibitor / dust inhibition aggregate.

The dissolution rate (%) can be used to determine the dissolution rate gradient. The dissolution rate gradient is simply the difference between the dissolution rate (%) of the uncoated core particles and the dissolution rate of the core particles of the dust suppression agglomerates. In other words, when the dissolution rate for core particles and dust suppressing aggregates not coated under specific conditions is obtained, the dissolution rate gradient is an absolute value obtained by subtracting the dissolution rate of the uncoated core particles from the dissolution rate (%) of the dust suppression agglomerates. Typically, the smaller the dissolution rate gradient, the better. The dust inhibitor should inhibit the dust formation of the core particles, but it is typically desired that the dust inhibitor has a minimal effect on the dissolution rate of the core particles.

Referring now to Table 4, the dust values of Examples V-X are significantly smaller than the dust values of Comparative Example A (uncoated Core Particle B). More specifically, the particulate inhibitors comprising the polyurethanes of Examples V-X encapsulate the core particles B to form the core particles B, as shown by the low dust values and high dust reduction gradients in Examples V-X, Prevents dust formation. In addition, the dust inhibitor comprising polyurethane does not significantly inhibit or interfere with the dissolution of core particles B, as evidenced by a low solubility gradient.

It is to be understood that the appended claims are not intended to be limited to the particular compounds, compositions, or methods described in the specification, which may vary between the specific embodiments included within the scope of the appended claims. For any Markush group dependent on the present disclosure in describing a particular feature or aspect of various embodiments, it is contemplated that different, specific, and / or unexpected results may be obtained for each Markush group independent of all other Markush members It should be appreciated that it can be obtained from each member of the group. Each member of the Makush family may be individually and / or in combination, providing appropriate support for certain embodiments within the scope of the appended claims.

It is also to be understood that any ranges and subranges depending on the various embodiments of the present invention are included independently and in their entirety within the scope of the appended claims and their values are not explicitly listed herein It is to be understood that all ranges including integer and / or fractional values therein are described and considered. Those skilled in the art will recognize that the recited ranges and sub-ranges fully describe and enable various embodiments of the present invention, and such ranges and sub-ranges may be added in related 1/2, 1/3, 1/4, 1/5, ≪ / RTI > By way of example only, a range of "0.1 to 0.9" may be further described as a lower 1/3, i.e. 0.1 to 0.3, a middle 1/3, i.e. 0.4 to 0.6, and an upper 1/3, These are individually and collectively embraced within the scope of the appended claims, and may be individually and / or entirely dependent upon, which provides adequate support for particular embodiments within the scope of the appended claims. In addition, it should be understood that such terms encompass subranges and / or upper or lower limits for terms that define or modify ranges, such as "above", "beyond", "below", "below", and the like. As another example, a range of "10 or more" essentially includes a subrange of 10 or more to 35, a subrange of 10 or more to 25, a subrange of 25 to 35, etc., and each subrange may be individually and / And may provide for appropriate support for particular embodiments within the scope of the appended claims. Finally, the individual numbers within the disclosed ranges may be dependent, providing appropriate support for certain embodiments within the scope of the appended claims. For example, a range of "1 to 9" includes various individual integers, such as 3, as well as individual numbers including a decimal point (or fraction), such as 4.1, which may be dependent, To provide adequate support for a particular embodiment within the category.

It is to be understood that the invention has been described in an illustrative manner, and that the terms used are intended to be essentially descriptive terms rather than limiting. Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

Claims (19)

A. core particles; And
B. a particulate inhibitor disposed around the core particles for inhibiting dust formation of the core particles and comprising polyurethane
;
A dust reduction aggregate having a dust reduction gradient of greater than 20% and a solubility gradient of less than 30 after one day of aging at 38 DEG C water. The dust inhibition aggregate according to claim 1, wherein the polyurethane is present in an amount of 0.3 to 5.5 parts by weight based on 100 parts by weight of the core particles. 3. A dust inhibition aggregate according to claim 2 having a dust reduction gradient of greater than 60% and / or a solubility gradient of less than or equal to 15 after one day of aging at 38 DEG C water. 4. The dust inhibition aggregate according to any one of claims 1 to 3, wherein the polyurethane comprises the reaction product of an isocyanate component and a polyol component. 5. The dust inhibition aggregate of claim 4, wherein the polyol component comprises a high molecular weight (HMW) polyol having a nominal functionality of 2.5 or more and a hydroxyl value of 20 to 300 mg KOH / g. 6. The dust inhibition aggregate of claim 5, wherein the HMW polyol has a viscosity of from 100 to 2000 cps at 25 占 폚. 7. The dust inhibition aggregate according to claim 5 or 6, wherein the polyol component is different from the HMW polyol and comprises a catalytic polyol derived from an amine-based initiator. 8. The dust inhibition aggregate according to any one of claims 4 to 7, wherein the isocyanate component comprises polymeric diphenylmethane diisocyanate and has an NCO content of about 31.5 weight percent. 9. The dust suppression aggregate according to any one of claims 1 to 8, wherein the core particle comprises a fertilizer. 10. The dust-inhibiting aggregate according to any one of claims 1 to 9, wherein the core particles comprise monoammonium phosphate and / or urea. A. providing core particles; And
B. Encapsulating the core particles with polyurethane to form dust suppression agglomerates having a dust reduction gradient of greater than 20% and a solubility gradient of less than 30 after one day of aging in water at 38 DEG C
And a dust inhibitor disposed around the core particles for inhibiting dust formation of the core particles and comprising a polyurethane. 12. The method of claim 11, wherein the polyurethane is present in an amount of 0.3 to 5.5 parts by weight based on 100 parts by weight of the core particles. 13. The process of claim 12, wherein the dust inhibition aggregate has a dust reduction gradient of greater than 60% and / or a solubility gradient of less than or equal to 15 after one day of aging in water at 38 占 폚. 12. The process of claim 11, wherein encapsulating the core particles with polyurethane is further defined as reacting the isocyanate component and the polyol component to form a polyurethane, wherein the polyol component has a nominal functionality of 2.5 or greater and 20 to 300 mg KOH / g Of the high molecular weight (HMW) polyol having a hydroxyl value and / or wherein the isocyanate component comprises a polymeric diphenylmethane diisocyanate and has an NCO content of about 31.5 weight percent. 15. The process of claim 14, wherein the polyol component is different from the HMW polyol and further comprises a catalytic polyol derived from an amine-based initiator. 16. The method of claim 14 or 15, further comprising heating at least one of the core particles, the isocyanate component, and the polyol component to a temperature greater than 40 DEG C before or simultaneously with mixing the isocyanate component and the polyol component How to. 17. The process according to any one of claims 14 to 16, wherein the isocyanate component and the polyol component are reacted with an isocyanate index of from 90 to 160. 18. The method according to any one of claims 11 to 17, wherein the core particles comprise fertilizer. Core particles and a dust inhibitor disposed around the core particles to inhibit dust formation of the core particles and comprising polyurethane wherein the polyurethane is present in an amount of from 0.3 to 5.5 parts by weight based on 100 parts by weight of the core particles And a reaction product of an isocyanate component and a polyol component, wherein the composition has a dust reduction gradient of greater than 20% and a solubility gradient of less than 30 after one day of aging in water at 38 DEG C,
A. the isocyanate component;
B. said polyol component being reactive with said isocyanate component for the production of polyurethane; And
C. The core particles
/ RTI >